Idle Speed/Mixture A/T

Inspection/Adjustment

Propane Enrichment Method

Automatic Transmission
1. Start engine and warm up 10 normal operating temperature; the cooling fan will come on.





2. Remove the vacuum hose from the intake air control diaphragm and clamp the hose end.
3. Connect a tachometer.





4. Disconnect # 20 vacuum hose from 2-way joint between the frequency solenoid valve C and vacuum hose manifold, and plug the vacuum hose as shown.
Disconnect # 20 vacuum hose from 2-way joint between the frequency solenoid valve C and throttle controller, and plug the hose of the frequency solenoid valve side. Connect a vacuum pump to the hose of throttle controller and apply vacuum of more than 20 in. Hg.








5. Turn back the idle control screw end is flush with the bracket as shown.
With the headlights, heater blower, rear window defogger, cooling fan and air conditioner off, and transmission in "N" or "P", lower the idle speed as much as possible by turning the throttle stop screw.





6. Adjust the idle speed by turning the idle control screw to 630 ± 50 rpm.
7. Adjust the idle speed by turning the throttle stop screw to 700 ± 50 rpm.





8. With transmission in gear (except "P" or "N"), adjust the idle speed by turning adjusting screw A.

Idle speed should be:
675 ± 50 rpm (at high altitude)
700 ± 50 rpm (at low altitude)

9. Shift transmission to "N" or "P" position.





10. If equipped with air conditioner, adjust the idle speed by turning adjusting screw B to 700 ± 50 rpm with A/C on.
11. Stop the engine, remove the inside vacuum hose from the idle boost throttle controller and plug the hose.
12. Check the maximum engine speed by the propane enrichment method (Idle Speed/Mixture, steps 5 through 7).

RPM increase should be: 30 ± 10 rpm (in gear)

- If engine speed increases per specification, go to step 13.
- If engine speed does not increase per specification, adjust the enriched speed by turning the mixture screw (Idle Speed/Mixture, steps 8 through 21).

13. Stop engine. Close the propane control valve, remove all plugs, and reconnect all hoses.
14. Restart the engine and recheck idle speed.

NOTE: Raise the engine speed to 2,500 rpm 2 or 3 times in 10 seconds, and then check the idle speed.

Idle speed should be: 730 ± 50 rpm (in "N" or "P")

- If the idle speed is as specified, go to step 16.
- If the idle speed is not as specified, return to steps 4 through 12.





15. If the intake air temperature is above 65°C (149°F), go on to step 16 through 20.
16. Disconnect # 5 vacuum hose from the air suction valve and plug the hose.





17. Disconnect the # 27 vacuum hose from the pipe and plug the pipe.
Attach vacuum pump/gauge to the # 27 hose and apply vacuum.
18. With the engine idling, depress the push button on top of the propane device, then slowly open the propane control valve and check for vacuum.
There should be no vacuum.
- If there is no vacuum, check the air leak solenoid valve.
19. Reconnect all hoses.
20. Check the air bleed valve B.
21. Remove propane enrichment kit and reconnect air cleaner intake tube on the air intake duct.
22. Reinstall the mixture adjusting screw hole cap.
23. Recheck the idle speed with the A/T shift lever in gear.

Idle speed should be: 730 ± 50 rpm

24. Recheck the idle speed with the A/C on and with the shift lever in "P" or "N" position.

Idle speed should be: 750 ± 50 rpm

25. Recheck the idle speed with the A/C on and in gear.

Idle speed should be: 750 ± 50 rpm

26. If the idle rpm does not reach the specified idle speeds in steps 16 and 25 through 27, inspect the idle control system.